The overall objective of this project is to determine specific ways in which learning-induced changes in cortical representations contribute to the origins of and the expressions of acquired and developmental movement disorders and severe disorders of language, and to use that understanding as a source of insight for defining the forms of new neuroscience-based therapies designed to remediate them. We shall further develop and elaborate models of origin of a) focal dystonias of the hand (fDh); b) the usually-severe language disorder component of pervasive developmental disorders (PDDs); and c) some forms of generalized developmental dystonia and cerebral generate representations of learned stimuli and behaviors. It has already contributed to a growing appreciation of what postnatal functional self-organizing mechanisms contribute to human performance ability and disability and to the specific mechanisms that underlie these cortical cellular, synaptic and circuit changes process. Our principal focus is directed toward creating special models of "catastrophic plasticity" that have human neuropathology parallels. It is hypothesized that catastrophic cortical plasticity underlies the emergence of acquired movement disorders and repetitive strain injury symptoms in adults, and accounts for some of the major deficits of pervasive developmental disorders, developmental generalized dystonias and some forms of cerebral palsy. A more complete understanding of the neurological origins of the deficits contributed by the progressive learning in a defectively functionally self- organizing brains will provide crucial insights into possible forms of a new class of remediative training strategies and our understanding the physiological impacts of brain trauma, oxygen deprivation, or inherited weaknesses that contribute-along with learning to the origins of these severely disabling conditions. The continuation experiments are designed to deepen our understanding of the complex neurological origins of these common human maladies, and to provide us with information that will guide the development of remedial training strategies that could allow us to more effectively help many of these severely impaired individuals.